1. Field of the Invention
The present invention relates to a pharmaceutical composition, and in particular relates to a pharmaceutical composition for preventing or treating bone loss.
2. Description of the Related Art
Osteoporosis patients have been divided into two groups including postmenopausal osteoporosis and senile osteoporosis. Postmenopausal osteoporosis generally occurs in older aged women and is caused by female hormone deficiency. Senile osteoporosis generally occurs in older aged men and women. Human bone consists of a hard bone cortex and a soft medullary cavity that contains bone marrow, and the ratio of bone cortex and bone marrow has significant variations at different positions. Postmenopausal osteoporosis usually results in bones mainly consisting of bone marrow, thus leading to fractures, such as lumbar compression fractures and wrist fractures.
Postmenopausal osteoporosis is a metabolic bone disease suffered by older aged women. In clinical research, bone loss reaches up to 3˜5% annually for cases with hyposecretion of estrogen for climacteric women. Due to the prolonged lifespan of humans, the incidence trend of postmenopausal osteoporosis has been rising. Additionally, postmenopausal osteoporosis is primarily caused by numerous bone loss due to the deficiency of estrogen (approx. 3-6% or higher every year). In normal state, the excited hormone can stimulate osteoblast to generate cells, which depress the activity of the osteoclast, and stimulate osteoblast to keep the bone in a balanced state. In the absence of estrogen, numerous bones will be lost and calcium ion will be released from the bone, thus inhibiting the concentration of parathyroid hormone and leading to reduced composition of vital vitamins. This will reduce the calcium ion absorbed by the gastrointestinal tract, leading to a calcium ion imbalance, which adds to the rising trend of osteoporosis.
Although postmenopausal osteoporosis may be suppressed by hormone treatment, use of large amounts of hormone over a long period of time may cause serious side effects (Colditz G A, Hankinson S E, Hunter D J. The use of estrogen and progestins and the risk of breast cancer in postmenopausal women. N Eng J Med, 1995, 332:1589-1593; Grady D, Gebretsadik T, Kelikowske K. Hormone replacement therapy and endometrial cancer risk: a meta-analysis. Obstet Gynecol, 1995, 85:304-313). A pharmaceutical composition and method for treating or suppressing bone loss are thus required.